T-Flex : A large range of motion fully flexure-based 6-DOF hexapod

Abstract

Six degree of freedom manipulation provides full control over position and orientation, essential for many applications. However, six degree of freedom closed kinematic (parallel) manipulators either have a limited range of motion combined with a good repeatability when comprising flexure joints, or they have limited repeatability with a large workspace when using traditional rolling- or sliding-element bearings. Employing recent developments in large stroke flexures and design optimization, a fully flexure-based large range of motion hexapod robot has been designed. The resulting system allows for ±100 mm of translational and more than ±10 degrees of rotational range of motion in each direction combined with a small mechanism volume below 0.25 m³. Furthermore, a dedicated flexure-based design for the actuators combines high actuation forces without impairing precision, allowing for accelerations exceeding 10g. Experiments on a preliminary prototype validate the large workspace and confirm a high repeatability below 0.1 µm can be achieved, which is currently limited by electronics.